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Isolation and characterization of HsfA3, a new heat stress transcription factor of Lycopersicon peruvianum
Author(s) -
Bharti Kapil,
Schmidt Enrico,
Lyck Ruth,
Heerklotz Dirk,
Bublak Daniela,
Scharf KlausDieter
Publication year - 2000
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.2000.00746.x
Subject(s) - lycopersicon , transcription factor , isolation (microbiology) , heat stress , characterization (materials science) , stress (linguistics) , biology , botany , genetics , materials science , gene , bioinformatics , nanotechnology , linguistics , philosophy , zoology
Summary Stress‐induced transcription of heat shock proteins (Hsps) in eukaryotes is mediated by a conserved class of transcription factors called heat stress transcription factors (Hsfs). Here we report the isolation and functional characterization of HsfA3, a new member of the Hsf family. HsfA3 was cloned from a tomato heat stress cDNA library by yeast two‐hybrid screening, using HsfA1 as a bait. HsfA3 is a single‐copy gene with all the conserved sequence elements characteristic of a heat stress transcription factor. The constitutively expressed HsfA3 is mainly found in the cytoplasm under control conditions and in the nucleus under heat stress conditions. Functionally, HsfA3 behaves similarly to the already known members of tomato Hsf family. It is able to substitute yeast Hsf for viability functions and is a strong activator of Hsf‐dependent reporter constructs both in tobacco protoplasts and yeast. Finally, similar to the AHA motifs in HsfA1 and HsfA2, the activator function depends on four short peptide motifs with a central tryptophan residue found in the C‐terminal domain of HsfA3.